While tidal bores can occur any time a river is relatively shallow and the ocean tide is high, the strongest bores occur during equinoxes in September and March, when the sun, moon and Earth align, and their combined gravitational pull brings ocean tides to their peak.

This year a full moon combined with the spring equinox is expected to send a massive wave up the Amazon.

Bad news for boat owners who dock along the river, good news for someone like Serginho Laus — a pioneer of surfing the Pororoca who in 2003 broke records with 33.25-minute, 6.3-mile ride up the Araguari.

However, the Pororoca is not all fun and games — it's also a dangerous endeavor. Along with sending a wave upstream, the bore uproots trees and other heavy objects the might lurk under the surface. Not to mention when you’re done with your ride you’re basically stuck in the middle of the Amazon — a massive jungle filled with jaguars, crocodiles, snakes, piranhas, parasites and tropical diseases.

The Pororoca, which a local legend says was caused by three mischievous children traveling up the Amazon and playing practical jokes, has also inspired a number of festivals. The most famous of São Domingos do Capim in Para State.

Brazil isn’t the only country to experience a surfable tidal bore. In China, the Qiantang River and Hangzhou Bay create the Black Dragon, the world’s largest tidal bore that can reach up to 30 feet high and move as fast as 25 miles per hour.